Domier C W, Zhu Y, Dannenberg J, Luhmann N C
Department of Electrical and Computer Engineering, University of California at Davis, Davis, California 95616, USA.
Rev Sci Instrum. 2021 Mar 1;92(3):034714. doi: 10.1063/5.0040724.
Ultrashort Pulse Reflectometry (USPR) is a plasma diagnostic technique involving the propagation and reflection of ultrashort duration (∼few ns) chirps. The reflected packets pass through a multichannel filter with time-of-flight measurements performed on each of the filtered packets. A next generation USPR system is under development, spanning 28-75 GHz, for use on compact, short duration, magnetically confined fusion devices. This system presents a dramatic increase in performance compared with an earlier USPR system employed on the LLNL Sustained Spheromak Physics Experiment device more than a decade ago. The new system replaces upconverting mixers with higher power active multiplier chains to generate mm-wave transmitter chirps, with custom time-of-flight electronics reducing the time per measurement by a factor of 3X. Finally, the system is equipped with a field programmable gate array for data acquisition and analysis.
超短脉冲反射测量法（USPR）是一种等离子体诊断技术，涉及超短持续时间（约几纳秒）啁啾信号的传播和反射。反射的数据包通过一个多通道滤波器，并对每个滤波后的数据包进行飞行时间测量。下一代USPR系统正在研发中，频率范围为28 - 75吉赫兹，用于紧凑、短持续时间、磁约束聚变装置。与十多年前在劳伦斯利弗莫尔国家实验室（LLNL）的持续球马克物理实验装置上使用的早期USPR系统相比，该系统的性能有了显著提升。新系统用更高功率的有源倍频链取代了上变频混频器来产生毫米波发射啁啾信号，定制的飞行时间电子设备将每次测量时间缩短了三分之一。最后，该系统配备了一个现场可编程门阵列用于数据采集和分析。
